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協作目標：[[]]
- 原始：0位元組
- 沙盒：0位元組
来源搜索：“"腎小球"”——Google：网页、新闻、学术、图书、图片；百度：网页、新闻、学术、图片；知网工具书；JSTOR；维基百科图书馆
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內皮細胞
[编辑]腎小球的內皮細胞上有許多孔隙（fenestrae）。這些小孔孔徑約（70－100 nm）之間，可讓溶液、血漿及蛋白質通過，但無法使紅血球通過。
腎小球基底膜
[编辑]腎小球的內皮細胞下有一層非常厚的基底膜，約250－350nm左右。
足細胞（Podocytes）
[编辑]足細胞 Podocytes line the other side of the glomerular basement membrane and form part of the lining of Bowman's space. Podocytes form a tight interdigitating network of foot processes (pedicels) that control the filtration of proteins from the capillary lumen into Bowman's space.
The space between adjacent podocyte foot processes is spanned by a slit diaphragm formed by several proteins including podocin and nephrin. In addition, foot processes have a negatively charged coat (glycocalyx) that limits the filtration of negatively charged molecules, such as serum albumin.
The podocytes are sometimes considered the "visceral layer of Bowman's capsule", rather than part of the glomerulus.
腎小球内繫膜细胞（Intraglomerular mesangial cell）
[编辑]Intraglomerular mesangial cells are found in the interstitium between endothelial cells of the glomerulus. They are not part of the filtration barrier but are specialized pericytes that participate indirectly in filtration by contracting and reducing the glomerular surface area, and therefore filtration rate, in response mainly to stretch.
選擇性
[编辑]The structures of the layers determine their permeability-selectivity permselectivity. The factors that influence permselectivity are the negative charge of the basement membrane and the podocytic epithelium, and the effective pore size of the glomerular wall (8 nm). As a result, large and/or negatively charged molecules will pass through far less frequently than small and/or positively charged ones.[3] For instance, small ions such as sodium and potassium pass freely, while larger proteins, such as hemoglobin and albumin have practically no permeability at all.
血液入腎絲球
[编辑]Blood is carried out of the glomerulus by an efferent arteriole instead of a venule, as is observed in most other capillary systems. This provides tighter control over the blood flow through the glomerulus, since arterioles dilate and constrict more readily than venules, owing to arterioles' larger smooth muscle layer (tunica media).
Efferent arterioles of juxtamedullary nephrons (i.e., the 15% of nephrons closest to the medulla) send straight capillary branches that deliver isotonic blood to the renal medulla. Along with the loop of Henle, these vasa recta play a crucial role in the establishment of the nephron's countercurrent exchange system.
The efferent arteriole, into which the glomerulus delivers blood, empties into an interlobular vein.
鄰腎小球細胞（Juxtaglomerular cells）
[编辑]The walls of the afferent arteriole contain specialized smooth muscle cells that synthesize renin. These juxtaglomerular cells play a major role in the renin-angiotensin system, which helps regulate blood volume and pressure.
歷史
[编辑]In 1666, Malpighi first described the glomeruli and demonstrated their continuity with the renal vasculature (281,282). About 175 years later, Bowman elucidated in detail the capillary architecture of the glomerulus and the continuity between its surrounding capsule and the proximal tubule .[4]